1. Anton Pannekoek Institute for Astronomy , Amsterdam, Science Park 904, NL-1098 NH , the Netherlands
2. Department of Physics, Astrophysics, University of Oxford , Denys Wilkinson Building, Keble Road, Oxford OX1 3RH , UK
3. School of Mathematics, Statistics and Physics, Newcastle University , Herschel Building, Newcastle upon Tyne NE1 7RU , UK
4. Department of Physics, University of Warwick , Coventry CV4 7AL , UK
5. Center for Astro, Particle and Planetary Physics, New York University Abu Dhabi , Abu Dhabi 129188 , United Arab Emirates
6. School of Physics and Astronomy, University of Southampton , Southampton SO17 1BJ , UK
7. X-Ray Astrophysics Laboratory, NASA Goddard Space Flight Center , Code 662, Greenbelt, MD 20771 , USA
8. Independent
9. Institute of Astronomy, University of Cambridge , Madingley Road, Cambridge CB3 0HA , UK
10. Department of Astronomy, University of Maryland , College Park, MD 20742 , USA
11. CRESST II, NASA Goddard Space Flight Center , Greenbelt, MD 20771 , USA
12. NASA Goddard Space Flight Center , Greenbelt, MD 20771 , USA
13. Eureka Scientific, Inc. , 2452 Delmer Street, Oakland, CA 94602 , USA
14. MIT Kavli Institute for Astrophysics and Space Research , MIT, 77 Massachusetts Avenue, Cambridge, MA 02139 , USA
15. Dipartimento di Fisica, Universita‘ degli Studi di Cagliari , SP Monserrato-Sestu km 0.7, I-09042 Monserrato , Italy
16. Center for Astrophysics , Harvard & Smithsonian, 60 Garden St, Cambridge, MA 02138 , USA
17. Physics Department, Tor Vergata University of Rome , Via della Ricerca Scientifica 1, I-00133 Rome , Italy
18. INAF – Astronomical Observatory of Rome , Via Frascati 33, I-00040 Monte Porzio Catone , Italy
19. INFN – Rome Tor Vergata , Via della Ricerca Scientifica 1, I-00133 Rome , Italy
20. National Astronomical Observatories, Chinese Academy of Sciences , 20A Datun Road, Beijing 100101 , China
21. HEASARC , Code 6601, NASA/GSFC, Greenbelt, MD 20771 , USA